Direct current track relay for railway signaling systems



Sept. 22, '1931.

Filed Oct. l5 1950 2 Kn u Q MN Qm 2N1: vw 32 n 0 w 1m N o Patented Sept.22, 1931 UNITED STATES PATENT OFFICE WILLIAM D. HAILES, OF ROCHESTER,NEW YORK, ASSIGNOR T0 GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEWYORK DIRECT CURRENT TRACK RELAY FOR RAILWAY SIGNALING SYSTEMSApplication filed October 15, 1930. Serial No. 488,901.

This invention relates to direct current track circuits for railroads,and more particularly to a relay for such track circuits.

In the application of track circuit control to railway signaling, andthis is particularly true in single track signaling of theabsolutepermissive-block type, it is very important that the trackrelays, should be quick dropping and slow picking up. A track relay ofthe ordinary construction is apparently slow dropping and comparativelyquick in picking up, this because dropping of the relay due to theentrance of a train upon the track circuit is caused by shunting themain coil of the relay, and this coil when shunted acts as a slug orshort circuited winding which maintains the flux in the relay for anappreciable period of time. The reason why slow dropping of a relay andquick picking up of a relay is undersirable for controlling waysidesignals by track circuits, is because if a short train moves from onetrack circuit upon another track circuit it is possible that the trackcircuit cleared will have its relayi picked up before the track relay ofthe trac circuit being occupied has had time to drop, so that the resultis a momentary period where both of these track circuits manifest cleartraflic conditions, which may actually cause the next signal in the rearto mo- .mentarily indicate clear, and in the case of single tracksignalin where stick relays are employed may actua 1y eifect picking upor the dropping, of a stick relay and thereby reverse the direction oftrafiic set up.

In view of the above and other important considerations it is proposedin accordance with the present invention to employ an auxiliary magnetin the track relay which is only drawings and will in part be more specical- "ly described hereinafter.

tion.

In describing the invention in detail referencewill be made to theaccompanying drawings, in which;

Fig. 1 illustrates a track circuit having a relay embodying the presentinvention contained therein; and

I Fig. 2 shows a portion of a track circuit employing a relay ofmodified construction.

Referring to the drawings the track rails l are divided by insulatingjoints 2 into blocks, of which only the block I has been illustrated,this block I includes the usual track battery 3 and series resistance 4and a track relay T embodying the present inven- In the embodiment ofthe invention illustrated in Fig. l the track relay T comprises theusual soft iron cores 5 and 6 bolted to the back yoke 7 by nuts 8threaded on reduced extensions of the cores 5 and 6, the other end ofthese cores 5 and 6 terminating in the usual pole pieces. This corestructure is provided with main coils 9 and 10 connected in series to becumulative and auxiliar coils 11 and 12 also connected in series to ecumulative. The relay T includes the usual soft iron armature 15 pivotedat 16 and having fastened thereto but insulated therefrom a contact 17adapted to engage the front contact 18 or the back contact 19 conventionally shown by arrows. Below the armature 15 is provided, what may becalled a pull-down magnet of any suitable construction, and as showncomprises the cores 20 and 21, back yoke 22 and coils 23 and 24connected cumulatively in series. This pull-down magnet 2024 has itscoils connected in series with the auxiliary coils 11 and 12 of the maincore structure of the relay T, so that any change in magnetic flux inthe main core induces a current in the circuit including coils 11, 12,23 and 24 in series thereby producing a downward magnetic pull upon thearmature 15.

The various parts of the relay T are so de signed that even though thecurrent induced in the pull-down magnet 2024 is comparatively small itwill produce an appreciable effect on the 'operationof the armature 15.It is readily apparent that the movement of a train from left to rightinto the block I will shunt the main coils 5 and 6 of the relay T andthereby cause a sudden decrease in the flux passing through the auxilarycoils 11 p and 12, and this decrease in flux will induce a current inthe closed circuit including coils 11, 12, 23 and 24:, so that thepull-down magnet -24 is momentarily energized. The

magnetism emitted by the pull-down magnet 20-24, will, of course, act onthe armature 15 tending to pull it to its deenergized positlon, therebyreducing the time of action ofthe armature 15 duringdeenergization ofthe track relay T. When,'on the other hand, the train underconsideration passes out of the block Iithe sudden increase of directcurrent flowing to the main coils 9 andlO of the relay T will induce acurrent in the pull-down magnet-2024 thereby holding the armature 15 inits retracted position untilthe current in the pull-down magnet 2024:has substantially died down to a zero value. By,

reason of the fact that the magnetic circuit of the pull-down magnet issubstantially closed during the period when the armature .15- assumesits retractedposition, the efiect of the pull-downmagnet 2024c is verypronounced to retardpicking up of the arma 'ture 15,'whereas duringdeenergization of the track relay '1 the efi'ect'of the pull-down of atransformer of the closed core type, such x'asthe'transformer' as shownin Fig. 2.

The track relay T shown in Fig. 2 of the drawings has the axis of itspivot 31 arranged parallel to the two legs 32- (only one of which hasbeen shown) of the relay core, in conformity with the usual constructionof track relays of the direct current type. Y In order to multiply theefiect of the pull-down mag- -net: comprising cores 32 and coil 33 shownin Fig. 2 of the drawings especially in sofar as picking up of therelayT is concerned, the armature 34 is provided with an extension35preferably comprising non-magnetic metal,

such as brass, to the end of which is fastened an'armature 36 adapted tobe attracted by the pull-down magnet 3233.

V In this construction, although the efiect of the pull-down magnet 3233is not materially increasedin armature 34 :to its retracted position iscon- 7; Applicant has thus illustratedseveral em bodiments of his noveltrackrelay, which'is c'erned the action of thepull-down magnet '32.33to'prevent quick picking up of the armature 34; is. materiallyincreased, this because the armature 36 affords a material 1eeverageadvantage through which the armalture 36 may hold the armature 34C inits retracted'position.

" provi'ded with inductive means for preventing quickpicking upofthearmature of-such relay, and which inductive means increases the'speed ofretraction'of the armature upon deenergization of such relay, in Fig. 1the energy of induction is derivedfrom the main core structure of therelay, whereas in the arrangement shown in Fig. 2 the energy is derivedinductively from the stored energy 'in the closed core of transformer'30.

Having thusshown and described several 7 embodiments of the presentinvention, it is desiredto be I understood that the particularembodiments" oithe invention. illustrated havebeen selectedforthelpurposeeof facilitating disclosure and description thereof, andhave not been selected for the purpose of v illustrating the exactconstruction preferably employedin practicing the invention nor-havethey been illustrated to show the scope of the invention, and itis'to beunderstood thatvarlous changes, modifications "and additlons may be madeto adaptxtheinvention to the --part1cular problem encountered inpracticing the same, all without departing from the spirit or scope ofthe invention or theidea of lineans underlying the same, except asdemanded by the scope of the followingclaims.

What I claim as new is:.- I V 1. In a track circuit for railwayslgnallng,

:the combination with a track circuit source, and a track relay inserlestherewlth lncludmg amain; C011 and an auxiliary coll'opposing the actionof said main coilandinductively V coupled with said main coilf 7 .7

2. In a" relay, the comblnatlon withelectromotive power means, of acircuit for energizin said means a movable contact 0 erated by saidmeans, a second electro-motive power means which it energized opposesthe action .ofsa-id first mentioned electro-motive power means,and aiclosedicircuit for energizing said second electro-motive power meansinq ductively coupledito said first mentioned circuit.

3. In a relay, the combination with electroresponsive means, ofacircuitfor energizing said means, a movable-contact operated by said means, -asecond electro-responsive means which if'e'nergized opposes the actionofvsaid first mentioned electro-responsi-ve means, and

,4. In a relay, the combination with a movable contact biased toitsinactive position, of

an electro magnet foroperating saidcontact to its active position, acircu t for energizing said electro-magnet, a second electro-magnet tosaid first mena closed circluit 'for energizing said second 7electro-r'esponsivemeansinductively coupled p .to said first mentionedcircuit. 7 so far as operation of the operation of the magnet for urgingsaid contact toward its inactive position, and a circuit for said secondelectro-magnet inductively coupled to said first mentionedelectro-magnet.

6. In a relay, the combination with an armature biased to its inactiveposition, of an electro-magnet for operating said armature to its activeposition, a circuit for energizing said electro-magnet, a secondelectro-magnet for urging said armature toward its inactive position,and a circuit for said second electro-magnet inductively coupled to saidfirst mentioned circuit.

7 In a relay, the combination with an armature biased to its inactiveposition, of an electro-magnet for operating said armature to its activeposition, a circuit for energizing said electro-magnet, a secondelectro-magnet for urging said armature toward its inactive position,and a circuit for said second electro-magnet inductively coupled to saidfirst mentioned electro-magnet.

8. A track circuit for railways comprising, an insulated track section,a battery between the rails at one end of said section, a track relayhaving an armature and connected between the rails at the other end ofsaid section, a pull-down electro-magnet for urging the armature of saidrelay to its retracted position, and means for energizing said pull-downcoil only upon each change of current flow in said relay.

9. A track circuit for railways comprising, an insulated track section,a battery between the rails at one end of said section, a track relayhaving an armature and connected between the rails at the other end ofsaid section, a pull-down electro-magnet for urging the armature of saidrelay to its retracted position, and means inductively coupled to thecircuit of said relay to energize said pull-down electro-magnet onlyupon each change of current flow in said circuit.

10. A track circuit for railways comprising, an insulated track section,a battery between the rails at one end of said section, a track relayhaving an armature and connected between the rails at the other end ofsaid section, a pull-down electro-magnet for urging the armature of saidrelay to its retracted position, and means inductively coupled to saidrelay to energize said pulldown electro-magnet only upon each change ofcurrent flow in said circuit.

11. A track circuit for railways compris- WILLIAM D. HAILES.

